Question

The volume of gas decreases at constant temperature to 80% of the inital value. How does the pressure value change relative to the initial value

Answer 1

The pressure value changes 400 % relative to the initial value.

Step-by-step explanation:

Let suppose that the gas behaves ideally and represents a closed system, that is, a system with no mass interactions so that number of moles is conserved (
`n`). Since the variables involved in the isothermal process are pressure (
`P`) and volume (
`V`). Finally, the process is represented by the following relationship:

`P_(1)\cdot V_(1) = P_(2)\cdot V_(2)` (1)

Where:

`P_(1), P_(2)` - Initial and final pressures.

`V_(1), V_(2)` - Initial and final volumes.

If we know that
`P_(1) = P_(o)`,
`V_(1) = V_(o)` and
`V_(2) = 0.2\cdot V_(o)`, then the final pressure of the closed system is:

`P_(2) = P_(1)\cdot \left((V_(1))/(V_(2)) \right)`

`P_(2) = 5\cdot P_(o)`

The pressure value changes 400 % relative to the initial value.